A guy takes his wife to the doctor's for a check-up, as she's been acting a little strange.
"Well," says the doctor. "Its either Alzheimers or AIDS."
"What?!?" say the husband. "You can't tell the difference?"
"Yeah...they look a lot alike." says the doctor. "Tell you what, sir. Drive her out into the country and kick her out of the car. If she finds her way back home, don't fuck her."